Near-surface sensitive infrared reflection spectroscopy on SiO2 implanted with high-flux negative ions

Implantation of Cu negative ions of 60 keV induces frequency shifts of infrared (IR) vibration modes Of SiO2. Since the penetration depth of IR light is much larger than the projectile range of Cu- ions, conventional IR reflection spectroscopy detects little shifts. To evaluate the true shifts induced by the implantation, the near-surface sensitive IR reflection spectroscopy (NSS-IRRS) was applied using a suitable sample structure. Distinct shifts of -5, +6 and -44cm(-1), respectively, are observed in rocking, bending and stretching modes of Si-O-Si bonding Of SiO2. Ion-flux dependence was examined in the flux range of 0.95-100 muA/cm(2) with keeping the total fluence 3 x 10(16) ions/cm(2). Almost no ion-flux dependence is observed in the shifts of these modes, which is in contrast with the strong flux dependences of size- and depth-distributions of Cu nanoparticles in SiO2. (C) 2004 Elsevier Ltd. All rights reserved.